Creating 3D models of cultural heritage sites with terrestrial laser scanning and 3D imaging

Includes abstract.Includes bibliographical references.The advent of terrestrial laser-scanners made the digital preservation of cultural heritage sites an affordable technique to produce accurate and detailed 3D-computermodel representations for any kind of 3D-objects, such as buildings, infrastructure, and even entire landscapes. However, one of the key issues with this technique is the large amount of recorded points; a problem which was even more intensified by the recent advances in laser-scanning technology, which increased the data acquisition rate from 25 thousand to 1 million points per second. The following research presents a workflow for the processing of large-volume laser-scanning data, with a special focus on the needs of the Zamani initiative. The research project, based at the University of Cape Town, spatially documents African Cultural Heritage sites and Landscapes and produces meshed 3D models, of various, historically important objects, such as fortresses, mosques, churches, castles, palaces, rock art shelters, statues, stelae and even landscapes

Prediction of salting-out in liquid-liquid two-phase systems with ePC-SAFT: effect of the Born term and of a concentration-dependent dielectric constant

Knowledge on phase equilibria is of crucial importance in designing industrial processes. However, modeling phase equilibria in liquid-liquid two-phase systems (LLTPS) containing electrolytes is still a challenge for electrolyte thermodynamic models and modeling still requires a lot of experimental input data. Further, modeling electrolyte solutions requires accounting for different physical effects in the electrolyte theory, especially the change of the dielectric properties of the medium at different compositions and the related change of solvation free energy of the dissolved ions. In a previous work, the Born term was altered by combining it with a concentration-dependent dielectric constant within the framework of electrolyte Perturbed-Chain Statistical Associating Fluid Theory (ePC-SAFT), and hence called ‘ePC-SAFT advanced’. In the present work, ePC-SAFT advanced was validated against liquid-liquid equilibria (LLE) of LLTPS water+organic solvents+alkali halides as well as aqueous two-phase systems containing the phase formers poly (propylene glycol) and an ionic liquid. All the ePC-SAFT parameters were used as published in the literature, and each binary interaction parameter between ion-solvent was set to zero. ePC-SAFT advanced allowed quantitatively predicting the salt effect on LLTPS without adjusting binary interaction parameters, while classical ePC-SAFT or meaningless mixing rules for the dielectric constant term failed in predicting the phase behavior of the LLTPS

Catalytic Low-Temperature Dehydration of Fructose to 5-Hydroxymethylfurfural Using Acidic Deep Eutectic Solvents and Polyoxometalate Catalysts

HMF synthesis typically requires high temperature and is carried out in aqueous solutions. In this work, the low-temperature dehydration of fructose to HMF in different deep eutectic solvents (DES) was investigated. We found a very active and selective reaction system consisting of the DES tetraethyl ammonium chloride as hydrogen bond acceptor (HBA) and levulinic acid as hydrogen bond donor (HBD) in a molar ratio of 1:2 leading to a maximum HMF yield of 68% after 120 h at 323 K. The DES still contained a low amount of water at the initial reaction, and water was also produced during the reaction. Considering the DES properties, neither the molar ratio in the DES nor the reaction temperature had a significant influence on the overall performance of the reaction system. However, the nature of the HBA as well as the acidity of the HBD play an important role for the maximum achievable HMF yield. This was validated by measured yields in a DES with different combinations of HBD (levulinic acid and lactic acid) and HBA (choline chloride and tetra-n-alkyl ammonium chlorides). Moreover, addition of vanadium containing catalysts, especially the polyoxometalate HPA-5 (H8PV5Mo7O40) leads to drastically increased reaction kinetics. Using HPA-5 and the DES tetraethyl ammonium chloride—levulinic acid we could reach a maximum HMF yield of 57% after only 5 h reaction time without decreasing the very high product selectivity

Model-based optimization of multi-stage nanofiltration using the solution-diffusion–electromigration model

Nanofiltration is well suited to separate monovalent ions from multivalent ions, such as the separation of Li+ and Mg2+ from seawater, a potential lithium source for the production of lithium-ion batteries. To the best of our knowledge, there is no existing work on the optimization of a multi-stage membrane plant that differentiates between different ions and that is based on a validated transport model. This study presents a method for modeling predefined membrane interconnections using discretization along the membrane length and across the membrane thickness. The solution-diffusion–electromigration model was used as the transport model in a fundamental membrane flowsheet, and the model was employed to optimize a given flowsheet with a flexible objective function. The methodology was evaluated for three distinct separation tasks, and optimized operating points were found. These show that permeances and feed concentrations might cause negative rejections and positive rejections (especially for bivalent ions) depending on the ions’ properties and fluxes, thereby allowing for a favorable separation between the ions of different valence at optimized conditions. In an application-based case study for the separation of Li+ and Mg2+ from seawater, the method showed that under optimal conditions, the mol-based ratio of Mg2+/Li+ can be reduced from 2383 to 2.8 in three membrane stages

Genetic variability of Chilean and Peruvian surfclams (Donax marincovichi and Donax obesulus)

Exposed intertidal sandy beaches are commonly dominated by surf clams of the genus Donax. In Peru and Chile these bivalves play an important role for artisanal fisheries. Beside that, little is known about the taxonomy, biology, and the clams susceptibility to climatically induced changes. The taxonomic status of the two Donax species Donax marincovichi and Donax obesulus, distributed along the Peruvian coastline, is controversially discussed. As morphometric comparisons reveal no significant differences we possibly deal with a single rather than with two species. Furthermore, our knowledge on larval dispersal allowing gene flow among populations is scarce. Therefore, both putative Donax species were sampled at ten beaches along the coastline from northern Chile to northern Peru. Partial cytochrome oxidase I sequences were analysed in order to estimate the genetic distances between both putative species and to estimate the intraspecific gene flow along the coastline. Region specific patterns and the dependence on recruitment of local stocks are discussed

Global phylogeography of Oithona similis s.l. (Crustacea, Copepoda, Oithonidae) – A cosmopolitan plankton species or a complex of cryptic lineages?

Traditionally, many small-sized copepod species are considered to be widespread, bipolar or cosmopoli- tan. However, these large-scale distribution patterns need to be re-examined in view of increasing evi- dence of cryptic and pseudo-cryptic speciation in pelagic copepods. Here, we present a phylogeographic study of Oithona similis s.l. populations from the Arctic Ocean, the Southern Ocean and its northern boundaries, the North Atlantic and the Mediterrranean Sea. O. similis s.l. is considered as one of the most abundant species in temperate to polar oceans and acts as an important link in the trophic network between the microbial loop and higher trophic levels such as fish larvae. Two gene frag- ments were analysed: the mitochondrial cytochrome oxidase c subunit I (COI), and the nuclear ribosomal 28 S genetic marker. Seven distinct, geographically delimitated, mitochondrial lineages could be identi- fied, with divergences among the lineages ranging from 8 to 24%, thus representing most likely cryptic or pseudocryptic species within O. similis s.l. Four lineages were identified within or close to the borders of the Southern Ocean, one lineage in the Arctic Ocean and two lineages in the temperate Northern hemi- sphere. Surprisingly the Arctic lineage was more closely related to lineages from the Southern hemi- sphere than to the other lineages from the Northern hemisphere, suggesting that geographic proximity is a rather poor predictor of how closely related the clades are on a genetic level

Expression of genes encoding cytotoxic cell-associated serine proteases in thymocytes

A family of homologous serine esterases designated granzyme A-H and the pore-forming protein perforin are present in cytoplasmic granules of mature peripheral cytolytic T lymphocytes and natural killer cells. In vivo, the majority of cytotoxic T cells containing these granule-associated proteins are of the CD4−CD8+ phenotype. It is generally assumed that these cells are derived from immature CD4−CD8− thymocytes. However, the precise intrathymic differentiation steps leading to functionally mature cytotoxic T cells are unclear. Thus we decided to analyze the expression of genes in the thymus which are preferentially expressed in mature cytotoxic cells, i.e. granzyme A, granzyme B, and perforin. In situ hybridization on tissue sections revealed the expression of genes coding for granzyme A and granzyme B in the thymus. No evidence was found, however, for thymocytes expressing the perforin gene. Granzyme A and granzyme B mRNA positive cells in the thymus are almost exclusively CD4−CD8− thymocytes, particularly of the CD3− IL2R− phenotyp